1 / 39

Detector Issues

Detector Issues. H. Wieman Feb. 7, 2002 STAR Collaboration Meeting. Outline. Detectors under consideration BNL Detector R&D Workshop Nov. 01 Some detector decisions TPC replacement? Option for increased capability Are there fundamental limits at 40X luminosity upgrade Progress

kirsten-horn
Download Presentation

Detector Issues

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Detector Issues H. Wieman Feb. 7, 2002 STAR Collaboration Meeting

  2. Outline • Detectors under consideration • BNL Detector R&D Workshop Nov. 01 • Some detector decisions • TPC replacement? • Option for increased capability • Are there fundamental limits at 40X luminosity upgrade • Progress • Tests of micro pattern gas detectors • Active Pixel Sensor (APS) development

  3. Upgrade considerations • Build large TOF barrel (RPC ALICE/STAR R&D) • Install high precision inner vertex detector • Extend high quality forward tracking

  4. Upgrade considerations • Forward RICH, Yale • TPC replacement plus RICH - Nikolai Smirnoff • High speed FEE/RDO for current TPC

  5. RHIC Detector WorkshopNov 13-14, 2001 Semiconductor Vertex Tracking Rene Bellwied, Wayne State U. Gas Tracking Detectors Itzhak Tserruya, Weitzmann Inst. Particle Identification Hideki Hamagaki, Univ. Tokyo Trigger/Data Acquisition James Nagle, Columbia U.

  6. Detector Decisions • Present TPC vs Replacement • Can the present TPC work with the X40 luminosity upgrade • If TPC is replaced what are the trade offs, what are the physics benefits

  7. Can the present TPC handle X40 luminosity upgrade • Space charge induced drift distortion? • Observed DCA = 2.7 mm from Space Charge (Jamie Dunlop showed dependence on CTB scaler rate) • Space Charge depends on beam current not interaction rate (charge comes from upstream background) • Expect 12 mm with full 110 bunches x 109 ions • Jamie can correct 2.7 mm to 250 microns • DCA RMS does not increase with scaler rate • Conclusion: Distortion Problem is probably not a show stopper

  8. Can the present TPC handle X40 luminosity upgrade • Wire aging? • Depends on track multiplicity and gate open rate • This depends more on FEE/RDO rates than luminosity • 2kHz of central collisions – 4 years to reach limit of 0.1 Coul/cm on inner wires • Conclusion: Wire aging probably not a show stopper • Tracking problems from pileup?

  9. Present TPC vs replacement • Conclusion: Luminosity upgrade does not force a decision • Remains a question of physics priorities • Additional room for detectors with improved particle ID vs expense and energy • What improvements are possible using present TPC with new high rate FEE/RDO/DAQ and increased trigger capability?

  10. Smirnov Mini TPC

  11. Smirnov Mini TPC plus pad planes

  12. Detector replacement for TPC

  13. Replacement TPC, Technical issues • Is pure silicon better – probably too expensive and gives poorer low momentum resolution • The outer pad chambers – how many needed for adequate tracking and how expensive • Drift gas CF4 vs CH4 • Micro pattern readout – robustness with heavily ionizing tracks • Development needs and an early R&D progress report next>>

  14. Experimental set-up I.Giomataris,G.Smith,B.Yu Micro-pattern gas chamber readout for TPC

  15. Micro-photograph of Micromegas I.Giomataris,G.Smith,B.Yu 5 m copper, 25 m diameter holes, 50 m pitch 50 m tall Kapton pillar Pillar spacing normally 1mm ( 2mm on test sample) 50 m

  16. Anode plane: Al strips with pitch 0.95 mm I.Giomataris,G.Smith,B.Yu Center 12 strips bussed together, to preamplifier. Load  150 pF. Rest of strips grounded for present measurements. 152 mm Active area of micromegas mesh Section used for measurements (12 mm wide by 70mm) 152 mm

  17. Measurement instrumentation I.Giomataris,G.Smith,B.Yu Collimator (25 m, 100 m, 1 mm) Monochromator Energized X-ray source Detector

  18. Charge and Gain vs HT I.Giomataris,G.Smith,B.Yu

  19. +ve ion transmission I.Giomataris,G.Smith,B.Yu Must check if this is an issue for a small TPC

  20. Comments I.Giomataris,G.Smith,B.Yu • Micromegas mesh tested in Ar/20%CO2 and pure CF4 • Gas gain ~ 7,000 achieved in Ar/20%CO2 and ~ 300 in CF4 • 2mm post spacing may limit upper voltage, and hence gain, with CF4 • Resn of 16% and 27% FWHM in Ar/20%CO2 and pure CF4 at 5.4 keV • Positive ion feedthrough ~ 1% with ED = 200 V cm-1 • Collimated beam  cyclic gain change (~ 3%) across mesh holes • Tests continue: Ar/10%CH4, Ar/20%DME, ~ 10ns shaping, ion drift velocity, local gain variation, lateral diffusion….

  21. GEM Detector Courtesy of F. Sauli (CERN) N. Smirnov/ C. Woody Additional GEM foils will be used to construct readout detector for TPC Drift Cell

  22. GEM TPC F.Sauli (CERN) Narrow pad response function (Ds ~ 1 mm): Improved multi-track resolution Fast signals (no ion tail) DT~20 ns : F Intrinsic multi-track resolution DV ~ 1 mm3 (Standard MWPC TPC ~ 1 cm3) N. Smirnov/ C. Woody

  23. TPC Readout Plane and Electonics P.O’Connor & Bo Yu (BNL) Readout Pads DR ~ 1 cm f ~ 2 mm Segmentation driven largely by resolution

  24. VUV Spectrometer Measures optical transmission down to 120 nm Bob Azmoun and Craig Woody

  25. TOF Barrel • RPC plate technology (50 ps), different then current installed systems that have problems • Rice/ALICE • Bill Llope, Jose Lamas-Velverde (thesis), Geary Eppley • ALICE • Beam testing at BNL • Test slat in STAR • Outstanding issues – a TDC?

  26. Strawman / Potential layouts • Strawman technology = Silicon Strip • double-sided Silicon Strip detector, 100 micron pitch • 5 by 5 cm active area, 1000 channels/wafer • 300+320 wafers (see layout below) • 0.8 and 0.75 m2 of active Silicon, respectively • potential location:in front of FTPC • 5 layers (z=60,80,100,120,140 cm ; r=10,15,20,25,30 cm) • h = 2.3-4.0 (320,000 channels) • potential location: behind FTPC • 5 layers (z=350,375,400,425,450 cm ; r=20 cm all planes) • h = 3.5-5.0 (300,000 channels) Bellwied, November 2000

  27. Potential Layouts • two ‘stations’ in front and behind the FTPC • develop a quasi-circle • use single-sided Si • have FEE on disk edges • use TAB Technology ? Bellwied, June 2001

  28. RICH Detectors • Continuation of STAR RICH program • Located forward or • If TPC removed then in the cylinder • Gerd Kunde, Nikolai Smirnoff, Jamie Dunlop, Brian Lasiuk of Yale • Possible Yale development of CsI photo cathode production

  29. RICH Development, Yale • Investigation of CVD Diamond replacement for Cs-I by Brian Lasiuk Hamamatsu R7639

  30. Faster TPC readout • Tonko next talk • Interest by Tonko, Fred and Hank • Low impact solution to high luminosity operation

  31. Active Pixel Sensor (APS) • 20 m square pixels • 5 chips per slat • 90 million pixels • 40 m thick chips 5.6 cm 8 cm

  32. B A e- A-A’ B-B’ B’ A’ MEMOSA APS A Monolithic Active Pixel Sensor for Charged Particle Tracking and Imaging using Standard VLSI CMOS TechnologyJ.D. Berst, B. Casadei, G.Claus, C.Colledani, W.Dulinski, Y.Hu, D.Husson, J.P.Le Normand, R.Turchetta and J.L.RiesterLEPSI, IN2P3/ULP, Strasbourg, FranceG.Deptuch1, S.Higueret, M.WinterIReS, IN2P3/ULP, Strasbourg, France1vistitor from UMM, Cracow, Poland

  33. 128X128 pixels 0.25 m CMOS TSMC through MOSIS 4 styles row selection shift register column selection shift register n well collection nodes First chip – tested and works S. Kleinfelder

  34. SK chip design Cg • 4 pixel styles • Added FET acts as • Sample and hold (off or on) or • Capacitance isolator (TX held constant at intermediate voltage) Vsg Cd capacitance isolator Cg Cd Vsg drops to Vthreshold and any additional charge spills to drain (Cg). Only Cg is reset Copy of MIMOSA style

  35. LBL APS test with 1.5 GeV/c e-beam 17 e RMS per pixel

  36. LBL APS measured MIP signal Sums of 25 pixel regions centered on pixels with ADC  7 Same sums with empty frames Background subtracted APS signal with Bichsel calculation for 8 mm Si • Conclusion, signal to noise is good enough to get good efficiency without excessive false hits • The above analysis is with CDS and leakage current subtraction

  37. Summary • Present TPC will probably handle luminosity with new electronics • Forward tracking and inner vertex improve physics reach without disruption • Improved particle ID possible at mid rapidity with RICH, Aero gel etc. - but must replace TPC to free up real estate

  38. Leakage Current • Mean pixel current 0.9 fA or 5600 e/sec • Q leakage = 1 MIP in 70 ms • Negligible with cooling (preliminary), i.e. won’t need correction for zero suppress

  39. 0 0 0 0 0 0 4 4 4 4 4 4 8 8 8 8 8 8 Pion-Kaon separation Kaon-Protonseparation TOF s~100 ps 0 - 2.5 0 - 5 RICH n=1.004 5 - 17 17 - Aerogel n=1.007 1 - 5 5 - 9 Extended PID with Aerogel Y. Miake Aerogel together with TOF can extend the PID capability up to ~ 10 GeV/c

More Related